SMOOTH EMERGENCE FROM GENERAL ANESTHESIA

Anesthesiologists prefer their patients to have a gentle transition from the anesthetized state into the awake state. The desired goal is “smooth emergence.” When the general anesthetic requires an endotracheal tube, an issue is how to awaken the patient with minimal patient coughing and bucking while the tube remains in the trachea. Coughing and bucking are associated with increases in blood pressure and heart rate, as well as increased intrathoracic pressure, intracranial pressure, intraocular pressure, and increased bleeding or edema in head and neck surgeries.

An anesthesia colleague wrote to me several months ago, asking for my recommendations for achieving smooth emergence. His question prompted me to write this column.

In a previous column I opined on the virtues of awake extubation rather than deep extubation. I remain convinced that awake extubation is the preferred and safest practice for almost every patient. What can we do to reduce the agitation, coughing, bucking, hypertension, and tachycardia that can occur with awake extubation?

I’ve performed countless general anesthetics for surgeries requiring smooth emergence, specifically carotid endarterectomies, rhinoplasties, facelifts, craniotomies, thyroidectomies, and other head and neck procedures. In each of these surgeries, the surgeon has an intense interest in a gentle anesthesia wake-up, free of coughing, bucking, or hypertension.

 Miller’s Anesthesia (2015, Eighth edition, Chapter 70, 2158-99) discusses this topic in the chapter “Anesthesia for Neurologic Surgery,” written by lead author John C. Drummond. The chapter states the following:

1. “There is a paucity of systematically obtained clinical data to give a perspective to the actual magnitude of the risks associated with emergences that are not considered smooth.”
2. “We encourage trainees to include in their anesthetic technique as much narcotic as is consistent with spontaneous ventilation at the conclusion of the procedure.”
3. “We also have the bias that patients emerge more rapidly and smoothly when the last inhaled anesthetic to be withdrawn is nitrous oxide and that clinicians should seek to avoid the ‘neither here nor there’ phase of anesthesia that occurs in patients who are stimulated in the face of residual exhaled concentrations of volatile anesthetic on the order of 0.2 to 0.3 MAC.”
4. “A common practice among neuroanesthetists near the conclusion of a craniotomy is the relatively early discontinuation of the volatile anesthetic with supplementation, if necessary, of residual nitrous oxide with propofol by either bolus increments or infusion at rates in the range of 12.5 to 25 μg/kg/hr.”
5. “We commonly administer 1.5 mg/kg of intravenous lidocaine just before the head movement associated with applying the dressing.”
6. “Because of the premium placed on minimizing coughing and straining and hypertension, there may be a temptation to extubate from the trachea before complete recovery of consciousness. This may be acceptable in some circumstances. However, it should be undertaken with caution . . . it would, in general, be best to wait until the likelihood of the patient’s recovery of consciousness is confirmed or until patient cooperation and airway reflexes are likely to have recovered.”

I’d make the following observations to adapt these recommendations to non-neurosurgical patients:

1. It’s true there’s a paucity of data on the “best” way to achieve smooth emergence. Multiple papers have been published, each studying a small series of patients and examining a different regimen for emergence. The number of patients in these series is small, and none of the papers are linked to improved outcomes.
2. Regarding the appropriate amount of narcotic, I recommend dosing the narcotic as required to treat post-operative pain, and no more. In certain surgeries such as a rhinoplasty or a facelift, the surgeon will inject local anesthetic to blunt the bulk of postoperative pain. Additional intravenous narcotic may decrease the stimulus of an endotracheal tube in situ, but the extra narcotic doses come with the risk of increased narcotic side effects, i.e. nausea and sedation.
3. Contrary to the recommendations in Miller’s Anesthesia, my practice for years has been to discontinue nitrous oxide first, and to continue a low inspired concentration of 1% sevoflurane in 100% oxygen for the last five minutes of general anesthetics. I’ve found it effective for smooth emergence, following the additional suggestions listed and numbered in the second half of this column below. In addition, the 100% oxygen supplies an extra margin of safety prior to extubation.

Based on 32 years of practice and over 25,000 personally administered anesthetics, these are my suggestions to maximize the smooth emergence of intubated patients:

1. Utilize the “no touch” extubation technique as described by Tsui in Anesthesia and Analgesia in 2004. At the conclusion of adenotonsillectomy in children, once volatile anesthetics were discontinued, no further stimulation was applied to the patients, i.e. no suctioning, or repositioning. No laryngospasm, oxygen desaturation, or severe coughing occurred in any patient. Sheta also reported on this “no touch” technique in a prospective, randomized, single-blinded, comparative study. Sixty adult nasal or sinus surgery patients were randomized to standard awake intubation technique vs. a “no touch” extubation technique. There was no laryngospasm among patients who were extubated with the “no touch” technique. The control group had a higher statistical incidence in the number and severity of desaturation episodes, incidence of non-purposeful movement, biting, and hoarseness (P< 0.05). Significant oozing from the wound was less in the “no touch” group. (P < 0.05). Hemodynamic responses (tachycardia or hypertension) prior to extubation were significantly less in the “no touch” group (P<0.05).
2. Utilize intratracheal lidocaine (e.g. 4 cc of 4% lidocaine) at the time of intubation.  Minogue showed that intratracheal lidocaine decreased coughing on emergence for anesthetics < 2 hours in duration.
3. If the patient begins to wake earlier than desired, administer 50 mg increments of propofol for the typical 70 kg adult patient, to deepen anesthetic depth temporarily as needed.
4. If the patient develops hypertension or tachycardia prior to extubation, administer 5-10 mg increments of labetolol IV as needed.
5. Your primary value regarding extubation must be safety. While a patient’s coughing or bucking may displease the surgeon, your clinical practice of anesthesia must be based on the maintenance of Airway-Breathing-Circulation. Waiting until your patient is awake enough to maintain their own airway safely is more important than trying to keep the surgeon happy because he or she doesn’t like to see any bucking.

Data exists to support the use of dexmedotomidine or remifentanil to smooth emergence. Because of the expense of these medications, neither is part of my routine extubation protocol. Representative studies on these two drugs include:

• Dexmedotomidine: Lee JS, et al, studied adults undergoing elective thyroidectomy under sevoflurane anesthesia. Patients were randomized to receive either dexmedetomidine 0.5 μg/kg IV (Group D, n = 70) or saline (Group S, n = 71), each combined with a low-dose remifentanil infusion ten minutes before the end of surgery. Results showed the addition of this single dose (0.5 μg/kg) of dexmedetomidine duringemergence from sevoflurane-remifentanil anesthesia was effective in attenuating coughing and hemodynamic changes, and did not exacerbate respiratory depression.

• Remifentanil: Lee JH, et al, studied seventy female patients undergoing thyroidectomy under general anesthesia using sevoflurane and remifentanil. Patients were randomly assigned to IV lidocaine(Group L, n=35) or remifentanil (Group R, n=35). In Group L, at the end of surgery both the sevoflurane and the remifentanil infusion were stopped, and lidocaine 5 mg/ml was administered IV. In Group R, the remifentanil infusion was continued until extubation. The incidence of cough during the emergence was significantly higher in the lidocaine group than in the remifentanil group (72.7% vs. 20.6%, P<0.001), and so was the grade of cough (P<0.001). The authors concluded that an infusion of remifentanil reduced responsiveness to the tracheal tube during emergence from general anesthesia more effectively than IV lidocaine in female patients undergoing thyroid surgery.

A recent study by Nath et al. showed a decrease in emergence coughing with by preloading of endotracheal tube cuffs with alkalinized lidocaine. Two hundred patients were randomly assigned to alkalinized lidocaine (2 ml 2% lidocaine + 8 ml of 8.4% sodium bicarbonate) or 10 ml of saline prefilled into the endotracheal tube cuff 90 minutes prior to intubation. Results showed a significantly decreased incidence of coughing on emergence in the lidocaine group. In addition, the study showed the incidence of coughing was inversely related to the amount of narcotic used in the anesthetic, i.e. more narcotic —> less emergence coughing.

Anesthesia practice is both an evidence-based science and an experienced-based art. There will be multiple recipes for smooth emergence. You may choose the advice from Miller’s Anesthesia, you may choose my recommendations from theanesthesiaconsultant.com, or you may choose an entirely different method that includes dexmedotomidine or remifentanil.

May all your patients emerge safely and smoothly.

May you, in the words of the Sade song, be a “Smooth Operator.”

 

The most popular posts for laypeople on The Anesthesia Consultant include:

How Long Will It Take To Wake Up From General Anesthesia?

Why Did Take Me So Long To Wake From General Anesthesia?

Will I Have a Breathing Tube During Anesthesia?

What Are the Common Anesthesia Medications?

How Safe is Anesthesia in the 21st Century?

Will I Be Nauseated After General Anesthesia?

What Are the Anesthesia Risks For Children?

 

The most popular posts for anesthesia professionals on The Anesthesia Consultant  include:

10 Trends for the Future of Anesthesia

Should You Cancel Anesthesia for a Potassium Level of 3.6?

12 Important Things to Know as You Near the End of Your Anesthesia Training

Should You Cancel Surgery For a Blood Pressure = 178/108?

Advice For Passing the Anesthesia Oral Board Exams

What Personal Characteristics are Necessary to Become a Successful Anesthesiologist?

 

*
*
*
*

Published in September 2017:  The second edition of THE DOCTOR AND MR. DYLAN, Dr. Novak’s debut novel, a medical-legal mystery which blends the science and practice of anesthesiology with unforgettable characters, a page-turning plot, and the legacy of Nobel Prize winner Bob Dylan.

KIRKUS REVIEW

In this debut thriller, tragedies strike an anesthesiologist as he tries to start a new life with his son.

Dr. Nico Antone, an anesthesiologist at Stanford University, is married to Alexandra, a high-powered real estate agent obsessed with money. Their son, Johnny, an 11th-grader with immense potential, struggles to get the grades he’ll need to attend an Ivy League college. After a screaming match with Alexandra, Nico moves himself and Johnny from Palo Alto, California, to his frozen childhood home of Hibbing, Minnesota. The move should help Johnny improve his grades and thus seem more attractive to universities, but Nico loves the freedom from his wife, too. Hibbing also happens to be the hometown of music icon Bob Dylan. Joining the hospital staff, Nico runs afoul of a grouchy nurse anesthetist calling himself Bobby Dylan, who plays Dylan songs twice a week in a bar called Heaven’s Door. As Nico and Johnny settle in, their lives turn around; they even start dating the gorgeous mother/daughter pair of Lena and Echo Johnson. However, when Johnny accidentally impregnates Echo, the lives of the Hibbing transplants start to implode. In true page-turner fashion, first-time novelist Novak gets started by killing soulless Alexandra, which accelerates the downfall of his underdog protagonist now accused of murder. Dialogue is pitch-perfect, and the insults hurled between Nico and his wife are as hilarious as they are hurtful: “Are you my husband, Nico? Or my dependent?” The author’s medical expertise proves central to the plot, and there are a few grisly moments, as when “dark blood percolated” from a patient’s nostrils “like coffee grounds.” Bob Dylan details add quirkiness to what might otherwise be a chilly revenge tale; we’re told, for instance, that Dylan taught “every singer with a less-than-perfect voice…how to sneer and twist off syllables.” Courtroom scenes toward the end crackle with energy, though one scene involving a snowmobile ties up a certain plot thread too neatly. By the end, Nico has rolled with a great many punches.

Nuanced characterization and crafty details help this debut soar.

Click on the image below to reach the Amazon link to The Doctor and Mr. Dylan: